package repository

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"time"

	"github.com/Wei-Shaw/sub2api/internal/service"
	"github.com/lib/pq"
)

type opsRepository struct {
	db *sql.DB
}

func NewOpsRepository(db *sql.DB) service.OpsRepository {
	return &opsRepository{db: db}
}

func (r *opsRepository) InsertErrorLog(ctx context.Context, input *service.OpsInsertErrorLogInput) (int64, error) {
	if r == nil || r.db == nil {
		return 0, fmt.Errorf("nil ops repository")
	}
	if input == nil {
		return 0, fmt.Errorf("nil input")
	}

	q := `
INSERT INTO ops_error_logs (
  request_id,
  client_request_id,
  user_id,
  api_key_id,
  account_id,
  group_id,
  client_ip,
  platform,
  model,
  request_path,
  stream,
  user_agent,
  error_phase,
  error_type,
  severity,
  status_code,
  is_business_limited,
  error_message,
  error_body,
  error_source,
  error_owner,
  upstream_status_code,
  upstream_error_message,
  upstream_error_detail,
  upstream_errors,
  duration_ms,
  time_to_first_token_ms,
  request_body,
  request_body_truncated,
  request_body_bytes,
  request_headers,
  is_retryable,
  retry_count,
  created_at
) VALUES (
  $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23,$24,$25,$26,$27,$28,$29,$30,$31,$32,$33,$34
) RETURNING id`

	var id int64
	err := r.db.QueryRowContext(
		ctx,
		q,
		opsNullString(input.RequestID),
		opsNullString(input.ClientRequestID),
		opsNullInt64(input.UserID),
		opsNullInt64(input.APIKeyID),
		opsNullInt64(input.AccountID),
		opsNullInt64(input.GroupID),
		opsNullString(input.ClientIP),
		opsNullString(input.Platform),
		opsNullString(input.Model),
		opsNullString(input.RequestPath),
		input.Stream,
		opsNullString(input.UserAgent),
		input.ErrorPhase,
		input.ErrorType,
		opsNullString(input.Severity),
		opsNullInt(input.StatusCode),
		input.IsBusinessLimited,
		opsNullString(input.ErrorMessage),
		opsNullString(input.ErrorBody),
		opsNullString(input.ErrorSource),
		opsNullString(input.ErrorOwner),
		opsNullInt(input.UpstreamStatusCode),
		opsNullString(input.UpstreamErrorMessage),
		opsNullString(input.UpstreamErrorDetail),
		opsNullString(input.UpstreamErrorsJSON),
		opsNullInt(input.DurationMs),
		opsNullInt64(input.TimeToFirstTokenMs),
		opsNullString(input.RequestBodyJSON),
		input.RequestBodyTruncated,
		opsNullInt(input.RequestBodyBytes),
		opsNullString(input.RequestHeadersJSON),
		input.IsRetryable,
		input.RetryCount,
		input.CreatedAt,
	).Scan(&id)
	if err != nil {
		return 0, err
	}
	return id, nil
}

func (r *opsRepository) ListErrorLogs(ctx context.Context, filter *service.OpsErrorLogFilter) (*service.OpsErrorLogList, error) {
	if r == nil || r.db == nil {
		return nil, fmt.Errorf("nil ops repository")
	}
	if filter == nil {
		filter = &service.OpsErrorLogFilter{}
	}

	page := filter.Page
	if page <= 0 {
		page = 1
	}
	pageSize := filter.PageSize
	if pageSize <= 0 {
		pageSize = 20
	}
	if pageSize > 500 {
		pageSize = 500
	}

	where, args := buildOpsErrorLogsWhere(filter)
	countSQL := "SELECT COUNT(*) FROM ops_error_logs " + where

	var total int
	if err := r.db.QueryRowContext(ctx, countSQL, args...).Scan(&total); err != nil {
		return nil, err
	}

	offset := (page - 1) * pageSize
	argsWithLimit := append(args, pageSize, offset)
	selectSQL := `
SELECT
  id,
  created_at,
  error_phase,
  error_type,
  severity,
  COALESCE(upstream_status_code, status_code, 0),
  COALESCE(platform, ''),
  COALESCE(model, ''),
  duration_ms,
  COALESCE(client_request_id, ''),
  COALESCE(request_id, ''),
  COALESCE(error_message, ''),
  user_id,
  api_key_id,
  account_id,
  group_id,
  CASE WHEN client_ip IS NULL THEN NULL ELSE client_ip::text END,
  COALESCE(request_path, ''),
  stream
FROM ops_error_logs
` + where + `
ORDER BY created_at DESC
LIMIT $` + itoa(len(args)+1) + ` OFFSET $` + itoa(len(args)+2)

	rows, err := r.db.QueryContext(ctx, selectSQL, argsWithLimit...)
	if err != nil {
		return nil, err
	}
	defer func() { _ = rows.Close() }()

	out := make([]*service.OpsErrorLog, 0, pageSize)
	for rows.Next() {
		var item service.OpsErrorLog
		var latency sql.NullInt64
		var statusCode sql.NullInt64
		var clientIP sql.NullString
		var userID sql.NullInt64
		var apiKeyID sql.NullInt64
		var accountID sql.NullInt64
		var groupID sql.NullInt64
		if err := rows.Scan(
			&item.ID,
			&item.CreatedAt,
			&item.Phase,
			&item.Type,
			&item.Severity,
			&statusCode,
			&item.Platform,
			&item.Model,
			&latency,
			&item.ClientRequestID,
			&item.RequestID,
			&item.Message,
			&userID,
			&apiKeyID,
			&accountID,
			&groupID,
			&clientIP,
			&item.RequestPath,
			&item.Stream,
		); err != nil {
			return nil, err
		}
		if latency.Valid {
			v := int(latency.Int64)
			item.LatencyMs = &v
		}
		item.StatusCode = int(statusCode.Int64)
		if clientIP.Valid {
			s := clientIP.String
			item.ClientIP = &s
		}
		if userID.Valid {
			v := userID.Int64
			item.UserID = &v
		}
		if apiKeyID.Valid {
			v := apiKeyID.Int64
			item.APIKeyID = &v
		}
		if accountID.Valid {
			v := accountID.Int64
			item.AccountID = &v
		}
		if groupID.Valid {
			v := groupID.Int64
			item.GroupID = &v
		}
		out = append(out, &item)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}

	return &service.OpsErrorLogList{
		Errors:   out,
		Total:    total,
		Page:     page,
		PageSize: pageSize,
	}, nil
}

func (r *opsRepository) GetErrorLogByID(ctx context.Context, id int64) (*service.OpsErrorLogDetail, error) {
	if r == nil || r.db == nil {
		return nil, fmt.Errorf("nil ops repository")
	}
	if id <= 0 {
		return nil, fmt.Errorf("invalid id")
	}

	q := `
SELECT
  id,
  created_at,
  error_phase,
  error_type,
  severity,
  COALESCE(upstream_status_code, status_code, 0),
  COALESCE(platform, ''),
  COALESCE(model, ''),
  duration_ms,
  COALESCE(client_request_id, ''),
  COALESCE(request_id, ''),
  COALESCE(error_message, ''),
  COALESCE(error_body, ''),
  upstream_status_code,
  COALESCE(upstream_error_message, ''),
  COALESCE(upstream_error_detail, ''),
  COALESCE(upstream_errors::text, ''),
  is_business_limited,
  user_id,
  api_key_id,
  account_id,
  group_id,
  CASE WHEN client_ip IS NULL THEN NULL ELSE client_ip::text END,
  COALESCE(request_path, ''),
  stream,
  COALESCE(user_agent, ''),
  auth_latency_ms,
  routing_latency_ms,
  upstream_latency_ms,
  response_latency_ms,
  time_to_first_token_ms,
  COALESCE(request_body::text, ''),
  request_body_truncated,
  request_body_bytes,
  COALESCE(request_headers::text, '')
FROM ops_error_logs
WHERE id = $1
LIMIT 1`

	var out service.OpsErrorLogDetail
	var latency sql.NullInt64
	var statusCode sql.NullInt64
	var upstreamStatusCode sql.NullInt64
	var clientIP sql.NullString
	var userID sql.NullInt64
	var apiKeyID sql.NullInt64
	var accountID sql.NullInt64
	var groupID sql.NullInt64
	var authLatency sql.NullInt64
	var routingLatency sql.NullInt64
	var upstreamLatency sql.NullInt64
	var responseLatency sql.NullInt64
	var ttft sql.NullInt64
	var requestBodyBytes sql.NullInt64

	err := r.db.QueryRowContext(ctx, q, id).Scan(
		&out.ID,
		&out.CreatedAt,
		&out.Phase,
		&out.Type,
		&out.Severity,
		&statusCode,
		&out.Platform,
		&out.Model,
		&latency,
		&out.ClientRequestID,
		&out.RequestID,
		&out.Message,
		&out.ErrorBody,
		&upstreamStatusCode,
		&out.UpstreamErrorMessage,
		&out.UpstreamErrorDetail,
		&out.UpstreamErrors,
		&out.IsBusinessLimited,
		&userID,
		&apiKeyID,
		&accountID,
		&groupID,
		&clientIP,
		&out.RequestPath,
		&out.Stream,
		&out.UserAgent,
		&authLatency,
		&routingLatency,
		&upstreamLatency,
		&responseLatency,
		&ttft,
		&out.RequestBody,
		&out.RequestBodyTruncated,
		&requestBodyBytes,
		&out.RequestHeaders,
	)
	if err != nil {
		return nil, err
	}

	out.StatusCode = int(statusCode.Int64)
	if latency.Valid {
		v := int(latency.Int64)
		out.LatencyMs = &v
	}
	if clientIP.Valid {
		s := clientIP.String
		out.ClientIP = &s
	}
	if upstreamStatusCode.Valid && upstreamStatusCode.Int64 > 0 {
		v := int(upstreamStatusCode.Int64)
		out.UpstreamStatusCode = &v
	}
	if userID.Valid {
		v := userID.Int64
		out.UserID = &v
	}
	if apiKeyID.Valid {
		v := apiKeyID.Int64
		out.APIKeyID = &v
	}
	if accountID.Valid {
		v := accountID.Int64
		out.AccountID = &v
	}
	if groupID.Valid {
		v := groupID.Int64
		out.GroupID = &v
	}
	if authLatency.Valid {
		v := authLatency.Int64
		out.AuthLatencyMs = &v
	}
	if routingLatency.Valid {
		v := routingLatency.Int64
		out.RoutingLatencyMs = &v
	}
	if upstreamLatency.Valid {
		v := upstreamLatency.Int64
		out.UpstreamLatencyMs = &v
	}
	if responseLatency.Valid {
		v := responseLatency.Int64
		out.ResponseLatencyMs = &v
	}
	if ttft.Valid {
		v := ttft.Int64
		out.TimeToFirstTokenMs = &v
	}
	if requestBodyBytes.Valid {
		v := int(requestBodyBytes.Int64)
		out.RequestBodyBytes = &v
	}

	// Normalize request_body to empty string when stored as JSON null.
	out.RequestBody = strings.TrimSpace(out.RequestBody)
	if out.RequestBody == "null" {
		out.RequestBody = ""
	}
	// Normalize request_headers to empty string when stored as JSON null.
	out.RequestHeaders = strings.TrimSpace(out.RequestHeaders)
	if out.RequestHeaders == "null" {
		out.RequestHeaders = ""
	}
	// Normalize upstream_errors to empty string when stored as JSON null.
	out.UpstreamErrors = strings.TrimSpace(out.UpstreamErrors)
	if out.UpstreamErrors == "null" {
		out.UpstreamErrors = ""
	}

	return &out, nil
}

func (r *opsRepository) InsertRetryAttempt(ctx context.Context, input *service.OpsInsertRetryAttemptInput) (int64, error) {
	if r == nil || r.db == nil {
		return 0, fmt.Errorf("nil ops repository")
	}
	if input == nil {
		return 0, fmt.Errorf("nil input")
	}
	if input.SourceErrorID <= 0 {
		return 0, fmt.Errorf("invalid source_error_id")
	}
	if strings.TrimSpace(input.Mode) == "" {
		return 0, fmt.Errorf("invalid mode")
	}

	q := `
INSERT INTO ops_retry_attempts (
  requested_by_user_id,
  source_error_id,
  mode,
  pinned_account_id,
  status,
  started_at
) VALUES (
  $1,$2,$3,$4,$5,$6
) RETURNING id`

	var id int64
	err := r.db.QueryRowContext(
		ctx,
		q,
		opsNullInt64(&input.RequestedByUserID),
		input.SourceErrorID,
		strings.TrimSpace(input.Mode),
		opsNullInt64(input.PinnedAccountID),
		strings.TrimSpace(input.Status),
		input.StartedAt,
	).Scan(&id)
	if err != nil {
		return 0, err
	}
	return id, nil
}

func (r *opsRepository) UpdateRetryAttempt(ctx context.Context, input *service.OpsUpdateRetryAttemptInput) error {
	if r == nil || r.db == nil {
		return fmt.Errorf("nil ops repository")
	}
	if input == nil {
		return fmt.Errorf("nil input")
	}
	if input.ID <= 0 {
		return fmt.Errorf("invalid id")
	}

	q := `
UPDATE ops_retry_attempts
SET
  status = $2,
  finished_at = $3,
  duration_ms = $4,
  result_request_id = $5,
  result_error_id = $6,
  error_message = $7
WHERE id = $1`

	_, err := r.db.ExecContext(
		ctx,
		q,
		input.ID,
		strings.TrimSpace(input.Status),
		nullTime(input.FinishedAt),
		input.DurationMs,
		opsNullString(input.ResultRequestID),
		opsNullInt64(input.ResultErrorID),
		opsNullString(input.ErrorMessage),
	)
	return err
}

func (r *opsRepository) GetLatestRetryAttemptForError(ctx context.Context, sourceErrorID int64) (*service.OpsRetryAttempt, error) {
	if r == nil || r.db == nil {
		return nil, fmt.Errorf("nil ops repository")
	}
	if sourceErrorID <= 0 {
		return nil, fmt.Errorf("invalid source_error_id")
	}

	q := `
SELECT
  id,
  created_at,
  COALESCE(requested_by_user_id, 0),
  source_error_id,
  COALESCE(mode, ''),
  pinned_account_id,
  COALESCE(status, ''),
  started_at,
  finished_at,
  duration_ms,
  result_request_id,
  result_error_id,
  error_message
FROM ops_retry_attempts
WHERE source_error_id = $1
ORDER BY created_at DESC
LIMIT 1`

	var out service.OpsRetryAttempt
	var pinnedAccountID sql.NullInt64
	var requestedBy sql.NullInt64
	var startedAt sql.NullTime
	var finishedAt sql.NullTime
	var durationMs sql.NullInt64
	var resultRequestID sql.NullString
	var resultErrorID sql.NullInt64
	var errorMessage sql.NullString

	err := r.db.QueryRowContext(ctx, q, sourceErrorID).Scan(
		&out.ID,
		&out.CreatedAt,
		&requestedBy,
		&out.SourceErrorID,
		&out.Mode,
		&pinnedAccountID,
		&out.Status,
		&startedAt,
		&finishedAt,
		&durationMs,
		&resultRequestID,
		&resultErrorID,
		&errorMessage,
	)
	if err != nil {
		return nil, err
	}
	out.RequestedByUserID = requestedBy.Int64
	if pinnedAccountID.Valid {
		v := pinnedAccountID.Int64
		out.PinnedAccountID = &v
	}
	if startedAt.Valid {
		t := startedAt.Time
		out.StartedAt = &t
	}
	if finishedAt.Valid {
		t := finishedAt.Time
		out.FinishedAt = &t
	}
	if durationMs.Valid {
		v := durationMs.Int64
		out.DurationMs = &v
	}
	if resultRequestID.Valid {
		s := resultRequestID.String
		out.ResultRequestID = &s
	}
	if resultErrorID.Valid {
		v := resultErrorID.Int64
		out.ResultErrorID = &v
	}
	if errorMessage.Valid {
		s := errorMessage.String
		out.ErrorMessage = &s
	}

	return &out, nil
}

func nullTime(t time.Time) sql.NullTime {
	if t.IsZero() {
		return sql.NullTime{}
	}
	return sql.NullTime{Time: t, Valid: true}
}

func buildOpsErrorLogsWhere(filter *service.OpsErrorLogFilter) (string, []any) {
	clauses := make([]string, 0, 8)
	args := make([]any, 0, 8)
	clauses = append(clauses, "1=1")

	phaseFilter := ""
	if filter != nil {
		phaseFilter = strings.TrimSpace(strings.ToLower(filter.Phase))
	}
	// ops_error_logs primarily stores client-visible error requests (status>=400),
	// but we also persist "recovered" upstream errors (status<400) for upstream health visibility.
	// By default, keep list endpoints scoped to client errors unless explicitly filtering upstream phase.
	if phaseFilter != "upstream" {
		clauses = append(clauses, "COALESCE(status_code, 0) >= 400")
	}

	if filter.StartTime != nil && !filter.StartTime.IsZero() {
		args = append(args, filter.StartTime.UTC())
		clauses = append(clauses, "created_at >= $"+itoa(len(args)))
	}
	if filter.EndTime != nil && !filter.EndTime.IsZero() {
		args = append(args, filter.EndTime.UTC())
		// Keep time-window semantics consistent with other ops queries: [start, end)
		clauses = append(clauses, "created_at < $"+itoa(len(args)))
	}
	if p := strings.TrimSpace(filter.Platform); p != "" {
		args = append(args, p)
		clauses = append(clauses, "platform = $"+itoa(len(args)))
	}
	if filter.GroupID != nil && *filter.GroupID > 0 {
		args = append(args, *filter.GroupID)
		clauses = append(clauses, "group_id = $"+itoa(len(args)))
	}
	if filter.AccountID != nil && *filter.AccountID > 0 {
		args = append(args, *filter.AccountID)
		clauses = append(clauses, "account_id = $"+itoa(len(args)))
	}
	if phase := phaseFilter; phase != "" {
		args = append(args, phase)
		clauses = append(clauses, "error_phase = $"+itoa(len(args)))
	}
	if len(filter.StatusCodes) > 0 {
		args = append(args, pq.Array(filter.StatusCodes))
		clauses = append(clauses, "COALESCE(upstream_status_code, status_code, 0) = ANY($"+itoa(len(args))+")")
	}
	if q := strings.TrimSpace(filter.Query); q != "" {
		like := "%" + q + "%"
		args = append(args, like)
		n := itoa(len(args))
		clauses = append(clauses, "(request_id ILIKE $"+n+" OR client_request_id ILIKE $"+n+" OR error_message ILIKE $"+n+")")
	}

	return "WHERE " + strings.Join(clauses, " AND "), args
}

// Helpers for nullable args
func opsNullString(v any) any {
	switch s := v.(type) {
	case nil:
		return sql.NullString{}
	case *string:
		if s == nil || strings.TrimSpace(*s) == "" {
			return sql.NullString{}
		}
		return sql.NullString{String: strings.TrimSpace(*s), Valid: true}
	case string:
		if strings.TrimSpace(s) == "" {
			return sql.NullString{}
		}
		return sql.NullString{String: strings.TrimSpace(s), Valid: true}
	default:
		return sql.NullString{}
	}
}

func opsNullInt64(v *int64) any {
	if v == nil || *v == 0 {
		return sql.NullInt64{}
	}
	return sql.NullInt64{Int64: *v, Valid: true}
}

func opsNullInt(v any) any {
	switch n := v.(type) {
	case nil:
		return sql.NullInt64{}
	case *int:
		if n == nil || *n == 0 {
			return sql.NullInt64{}
		}
		return sql.NullInt64{Int64: int64(*n), Valid: true}
	case *int64:
		if n == nil || *n == 0 {
			return sql.NullInt64{}
		}
		return sql.NullInt64{Int64: *n, Valid: true}
	case int:
		if n == 0 {
			return sql.NullInt64{}
		}
		return sql.NullInt64{Int64: int64(n), Valid: true}
	default:
		return sql.NullInt64{}
	}
}